Devices for saving or limiting the rate of fluids flow such as water are well known in the art. Said devices particularly comprise a connecting tube which is provided with an inlet portion having internal threads and with an outlet portion having external threads, the portion corresponding to the external threads being of a smaller diameter than the remainder of the body of the connecting tube, said connecting tube being provided with a helical spring of a shape and a strength suitable to allow the desired rate of flow and arranged within said tube, and a specially designed needle-type shutter, particularly of a stepped cylindrical shape, concentrically arranged within said spring such that at the inlet end of the shutter, there is formed a flange, on the internal part of which bears the spring surrounding the needle type shutter, said spring bearing at its lower portion on an internal shoulder formed in the connecting tube by a reduction of the diameter of the same.
The above mentioned flange arranged on the upper end of the needle type shutter, is provided with one or a plurality of axially extending holes for allowing the fluid flow to pass. During the operation of the prior art fluid rate of flow limiting devices, the vibration of the shutter due to passage of the fluid, produces a rattling effect on the body ends of the needle type shutter against the internal wall of the connecting tube and produces a noise level which is regarded as being of a high degree of annoyance. On the other hand, the holes provided for the passage of the fluid, are rapidly clogged and even completely obstructed in a relatively short period of time, particularly when the fluid is impure water. The above defects cause significant inconveniences because of the annoying noise of said prior art devices and because of the cumbersome and costly operation of frequently disassembling said connecting tubes in order to clean the fluid flow holes of the shutter.